How can one overcome feelings of low self-confidence and frustration after abandoning homosexuality, and can a Muslim who was practicing homosexuality get married?

Sodomy is a grave abomination that led to the destruction of the people of Lut. The question, "Why did my Lord choose me to be this way?" is from the whisperings of Satan, who leads one into sin and then attributes the sin to Allah. Allah does not approve of abominations for His servants; rather, He commands them to righteousness and helps them achieve it. One must abandon the whisperings of Satan and be keen on what benefits them, be strong in doing good deeds, and seek assistance from Allah. It is imperative to distance oneself from everything that reminds one of that abomination, to repent sincerely and earnestly to Allah. There is no objection to marriage after repentance, as it is more conducive to purity and chastity.